1. Field of the Invention
The invention relates to a method for interaction-free entanglement of quantum bits in quantum computers.
2. Description of the Related Art
Various methods are known for entangling quantum bits in quantum computers. By way of example, the quantum systems to be entangled may be transferred into the desired entangled state by means of physical interactions. A corresponding method is described in [6]. There, the ions enclosed in a linear ion trap can be prepared in an entangled state in a defined manner due to the Coulomb repulsion occurring between the ions.
A method for interaction-free entanglement of quantum systems is described in [15]. However, the significant disadvantage of this method can be seen in the fact that a classical information channel is required in this method.
In the method proposed in [1], neither an interaction nor a classical information channel is required in order to be able to transfer two quantum bits (qubits) into an entangled state. In this method, the preparation step essential for the process of entanglement consists of it being necessary to sufficiently quickly superpose a homogeneous magnetic field B, over the quantum bits to be entangled. However, a significant disadvantage of the method for state entanglement, proposed in [1], can be seen in the fact that, to this end, the magnetic field B, needs to be switched on and, thereafter, also needs to be switched off again in a defined manner. In practice, this is very complicated and connected with high costs.